CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (13,000)	$ (126,503)	$ (32,848)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation	126,583	121,644	119,441
Amortization	16,180	14,554	12,057
Straight-line rent adjustments	(5,166)	(1,989)	(2,686)
Provision for doubtful accounts		2,461	1,763
Non-cash lease termination revenue		(4,200)
Amortization of deferred compensation	6,212	6,925	5,709
Gain on debt extinguishment, net	(24,859)	0	0
Insurance recoveries in excess of property loss	(3,861)	(689)
Gain on sale of interests in real estate and non-operating real estate, net	(5,474)	(9,625)	(881)
Equity in income of partnerships	(8,289)	(11,375)	(14,367)
Gain on sale of real estate by equity method investee	(553)	(2,772)	(6,567)
Cash distributions from partnerships	22,570	9,421	16,849
Amortization of historic tax credits		(829)	(1,768)
Impairment of assets	1,455	129,365	55,793
Impairment of development land parcel	3,562
Impairment of mortgage loan receivable		8,122
Change in assets and liabilities:
Net change in other assets	(4,191)	(5,998)	(5,652)
Net change in other liabilities	223	6,352	(4,752)
Net cash provided by operating activities	111,392	134,864	142,091
Cash flows from investing activities:
Investments in consolidated real estate acquisitions		(17,611)
Cash proceeds from sales of real estate	50,407	13,730	77,778
Cash proceeds from sale of mortgage	8,000
Net proceeds from insurance claims related to damage to real estate assets	6,977	700
Cash distributions from partnerships of proceeds from real estate sold	879	19,727	30,265
Investments in partnerships	(72,939)	(58,112)	(73,434)
Investments in real estate improvements	(34,260)	(35,170)	(51,949)
Additions to construction in progress	(113,791)	(75,649)	(116,550)
Capitalized leasing costs	(568)	(12,022)	(6,066)
Distribution of financing proceeds from equity method investee	25,000	123,000	35,221
Additions to leasehold improvements and corporate fixed assets	(1,055)	(160)	(683)
Net cash used in investing activities	(131,350)	(41,567)	(105,418)
Cash flows from financing activities:
Net proceeds from issuance of preferred shares			286,847
Redemption of Series A Preferred Shares			(115,000)
Borrowings under revolving facilities	190,000	12,000	56,000
Repayments of mortgage loans and finance lease liabilities	(71,387)		(150,000)
Proceeds from mortgage loans		10,185
Principal installments on mortgage loans	(17,911)	(18,655)	(17,945)
Payment of deferred financing costs	(95)	(5,529)	(71)
Value of shares of beneficial interest issued	1,256	1,410	2,085
Dividends paid to common shareholders	(63,787)	(59,145)	(58,651)
Dividends paid to preferred shareholders	(27,375)	(27,375)	(27,403)
Distributions paid to Operating Partnership unit holders and noncontrolling interest	(3,004)	(6,949)	(6,970)
Value of shares retired under equity incentive plans, net of shares issued	(556)	(747)	(1,477)
Net cash provided by (used in) financing activities	7,141	(94,805)	(32,585)
Net change in cash, cash equivalents, and restricted cash	(12,817)	(1,508)	4,088
Cash, cash equivalents, and restricted cash, beginning of period	32,445	33,953	29,865
Cash, cash equivalents, and restricted cash, end of period	$ 19,628	$ 32,445	$ 33,953